城市道路粉尘、土壤及行道树的重金属污染特征

为了减轻汽车行驶导致的城市道路重金属污染。采用污染指数法分析、评价东京城市道路粉尘、行道树表层土壤的重金属污染特征。掌握道路受重金属污染的状况。探讨行道树树叶对重金属的捕获能力及树种间的差异．结果表明。东京市区道路粉尘的重金属浓度随交通量的增加而上升，且与道路土壤相比。道路粉尘的重金属浓度高．以Pb为代表的汽车污染在东京有减轻的趋势。但是仍然较高，说明Pb污染长期存在；而且。因尾气净化系统中使用Pt。从而引起Pt污染．行道树树叶的重金属浓度比对照点同树种的浓度高。不同树种浓度差异较大。杜鹃花蓄积重金属的能力强．因此，栽植蓄积重金属能力强的树种。可以在一定程度上控制重金属污染的扩散．

Heavy Metal Pollution of Dust, Topsoil and Roadside Tree Near by Main City Roadways

To effectively control heavy metal pollution of city roadways induced by motors, the pollution index method was adopted to analyze and evaluate the characteristics of heavy metal pollution of roadway dust and topsoil near by roadside trees, and grasp the status of heavy metal pollution of city roadways. The capability for the leaves of a roadside tree to capture heavy metals and the diversity of the capabilities of different trees were discussed. The results show that the heavy metal concentration of roadway dust in downtown Tokyo increases with the traffic, and it is higher in dust than in topsoil. There is the trend, i. e. , Pb pollution, representing car pollution, declines in Tokyo, but its concentration is higher and Pb pollution will exist for a long time. Moreover, Pt pollution has been brought about due to the use of Pt in the exhaust-purified system of motor vehicles. The heavy metal concentration is always higher in the leaves of roadside trees than in those of homologous trees in a contrast spot, and there is a great difference in the heavy concentration of inhomogeneous trees and Rhododendron oomurasak can accumulate more heavy metal. As a result, to plant trees that can accumulate more heavy metals can restrain the diffusion of heavy metal pollution of city roadways.